Vulcano Workshop 2010 - May, 23-29, 2010 UHE Cosmic Rays in the Auger Era UHE Cosmic Rays in the Auger Era Sergio Petrera, L'Aquila University email: sergio.petrera@aquila.infn.it
Vulcano Workshop 2010 - May, 23-29, 2010 UHE Cosmic Rays in the Auger Era UHE Cosmic Rays in the Auger Era Sergio Petrera, L'Aquila University email: sergio.petrera@aquila.infn.it Motivations Present status of the Pierre Auger Observatory The physics items: energy spectrum CR composition arrival directions Summary and outlook
The interest for UHECRs in three points E > 10 18 eV transition galactic/extragalactic origin GZK effect pointing to the sources (particle astronomy !?)
The interest for UHECRs in three points The interest for UHECRs in three points E > 10 18 eV transition galactic/extragalactic origin GZK effect pointing to the sources (particle astronomy !?)
The interest for UHECRs in three points E > 10 18 eV transition galactic/extragalactic origin GZK effect pointing to the sources (particle astronomy !?)
The interest for UHECRs in three points E > 10 18 eV transition galactic/extragalactic origin GZK effect pointing to the sources (particle astronomy !?)
The interest for UHECRs in three points E > 10 18 eV transition galactic/extragalactic origin GZK effect pointing to the sources (particle astronomy !?) + GZK reduces the horizon
AGASA: stopped Jan. 2004 HiRes: stopped Apr 2006 Auger: operating Telescope Array: starting the all-particle spectrum few/km sq per century ankle GZK UHE UHE
AGASA: stopped Jan. 2004 HiRes: stopped Apr 2006 Auger: operating Telescope Array: starting Exposures Exposures
The Pierre Auger Observatory
Auger South: the plan Auger South: the plan
2 area 3000 km 2 area 3000 km Vulcano Workshop
Auger detection techniques Nitrogen fluorescence detected as shower develops Particles detected as they reach ground Fluorescence Fluorescence (50 W light bulb @ c) (50 W light bulb @ c) nearly calorimetric direct view of shower evolution 10% duty cycle Acceptance depends on energy + atmosphere 12 particles over 20 km 2 ) (10 12 particles over 20 km 2 Surface Surface (10 ) 100% duty cycle Flat acceptance above threshold Indirect measurements of primary energy and mass (relies on simulation) Hybrid = surface + fluorescence Hybrid = surface + fluorescence
Observables at Auger
Observables at Auger
Observables at Auger
Energy Calibration SD energy calibration based on FD profiles “golden hybrid” events (independently detected) energy systematic error ~22 % mostly from systematics of the FD detector (fluorescence yield, atmospheric transparency...)
the Surface Detector Water Cherenkov tank Rotomolded polyethylene tank 10 m 2 x 1.2 m of ultrapure water in a light diffusing Tyvek liner, 3 PMTs Photonis (9’’ diameter); Autonomous unit: solar panel+battery, GPS timing, communication antenna, electronics Max 10 W power consumption
Schmidt Telescope the Fluorescence using 11 m 2 mirrors Detector UV optical filter (also: provide protection from outside dust) Camera with 440 PMTs (Photonis XP 3062)
Schmidt Telescope the Fluorescence using 11 m 2 mirrors Detector UV optical filter (also: provide protection from outside dust) Camera with 440 PMTs (Photonis XP 3062)
Auger 2010 Construction ended Apr. 2008 Enhancements for Detection @ Low Energies: HEAT (High Elevation Auger Telescopes) AMIGA (Auger Muon and Infill Array) + AERA array of radio detectors
Auger 2010 Construction ended Apr. 2008 Enhancements for Detection @ Low Energies: HEAT (High Elevation Auger Telescopes) AMIGA (Auger Muon and Infill Array) + AERA array of radio detectors New R&D: MW fluorescence detection [after Gorham et al., PR D 78 (2008) 032007] Towards an FD with 100% duty cycle?
ENERGY SPECTRUM ENERGY SPECTRUM
the Energy Spectrum PLB 685 (2010) 239 Cutoff at ~10 19.6 eV significant with > 30
the Energy Spectrum PLB 685 (2010) 239 Cutoff at ~10 19.6 eV significant with > 30
the Energy Spectrum Within the energy scale systematics
Comparison to Source Models
MASS COMPOSITION MASS COMPOSITION
Mass Composition: the principle photons X max protons Fe Energy
Mass Composition: the principle photons X max protons Data Fe X max Energy
Elongation Rate Measurement Auger and HiRes Xmax measurements are compatible within systematic uncertainties
Comparison with Hadronic Models PRL 104 (2010) 091101 ⇒ Mass composition getting heavier HiRes PRL 2010 “proton dominance above 1.6 EeV” but... difficult to compare with HiRes due to different definitions of observables.
Comparison with Hadronic Models PRL 104 (2010) 091101 More about Mass Composition by Analisa Mariazzi
Photons: upper limits Top down models strongly constrained
Neutrinos: Earth skimming ν τ
ARRIVAL DIRECTIONS ARRIVAL DIRECTIONS
Initial Anisotropy Searches ICRC 2007 Typical accuracy of reconstruction <1° No significant emission from Galactic Centre No broadband signals – e.g. Dipole – at any energy above 1 EeV e.g 1 < E < 3 EeV, Amplitude < 0.7% No clustering of the type claimed by AGASA No signal from BL Lacs as possibly seen by HiRes Summary: Previous reports have not been confirmed Summary: Previous reports have not been confirmed
Correlation with AGN's (2007) Based on a Prescribed Anisotropy Test: Correlation with Veron-Cetty-Veron AGN Catalog 20 out of 27 events E>57 EeV correlating within 3.1 degrees with z<0.017 AGN's Isotropy rejected with >99% C.L.
Correlation with AGN's (2010) Update of the Prescribed Anisotropy Test (correlation with VCV catalog of AGNs) 38% (21/55) correlate (post exploration) vs. 21% expected from isotropy correlation decreased but still incompatible with isotropy at 99% C.L.
More results on Correlations New paper in preparation: new catalogs, autocorrelation, CenA preliminary
Summary... High quality results on all the observables of UHECR's A comprehensive interpretation of the whole data still missing
Summary... High quality results on all the observables of UHECR's A comprehensive interpretation of the whole data still missing
Summary... High quality results on all the observables of UHECR's A comprehensive interpretation of the whole data still missing
Summary... High quality results on all the observables of UHECR's A comprehensive interpretation of the whole data still missing Much work to do... many more data....
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) Auger South: low energy extension HEAT (3 high elevation telescopes) AMIGA (SD infill + muon detectors) +... Auger North: at Lamar (CO) undergoing evaluation Go to space!
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) TA (Telescope Array) ~2.5 hours from SLC Auger South: low energy extension HEAT (3 high elevation telescopes) 576 scintillator detectors AMIGA (SD infill + muon detectors) +... 1.2 km interval 3 (+2) Auger North: at Lamar (CO) Communication undergoing evaluation Towers Go to space! 3 FD stations (atmospheric fluorescence telescopes) 30 km
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) TA (Telescope Array) Auger South Auger South: low energy extension HEAT (3 high elevation telescopes) AMIGA (SD infill + muon detectors) +... Auger North: at Lamar (CO) undergoing evaluation Go to space!
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) TA (Telescope Array) Auger South Auger South: low energy extension HEAT (3 high elevation telescopes) AMIGA (SD infill + muon detectors) +... Auger North Auger North: at Lamar (CO) undergoing evaluation Go to space!
Auger North
Auger North: comparison with other expts
Auger North: correlations above 60 EeV
Photon search
Auger North: Photon search
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) TA (Telescope Array) Auger South Auger South: low energy extension HEAT (3 high elevation telescopes) AMIGA (SD infill + muon detectors) +... Auger North Auger North: at Lamar (CO) undergoing evaluation Go to space! Go to space!
… and Outlook What's coming next?W hat's coming next? A new observatory: TA (Telescope Array) TA (Telescope Array) Auger South Auger South: low energy extension HEAT (3 high elevation telescopes) AMIGA (SD infill + muon detectors) +... Auger North Auger North: at Lamar (CO) undergoing evaluation Go to space! Go to space! Thanks
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